The \(\mathrm {USp}(2N)\)  \(N_f=4\)  SCFTs can be constructed as the low energy effective theory of type IIA superstrings in the presence D4, NS5, D6, and O6\(^-\)  branes generalizing the construction of [1]}. The M-theory lift of the D6 and O6\(^-\)  IIA brane configuration [2]} is a specific choice of complex structure of a \((T^2 \times \mathbb {C})/\mathbb {Z}_2\)  hyperkähler orbifold background. The M-theory lift of the D4 and NS5 branes is a single M5 brane intersecting the background except over points of \(T^2 \)  corresponding to NS5 branes. This intersection is the Seiberg-Witten curve, and the restriction of the holomorphic hyperkahler form to the curve is the Seiberg-Witten one-form. This is the spectral curve of a Hitchin system on the orbifolded torus with punctures [2]}.
